1. Field
One embodiment of the invention relates to an information processing apparatus and a nonvolatile semiconductor memory drive.
2. Description of the Related Art
In recent years, data storage devices, such as hard disks, have widely been used.
Jpn. Pat. Appln. KOKAI Publication No. 2006-196135 discloses a data storage device having a scramble/descramble function. This data storage device includes transmission/reception means, scrambler means, a hard disk, descrambler means, a memory, and initial value varying means. The transmission/reception means receives information from outside and transmits information in the data storage device to the outside. The scrambler means scrambles the information which the transmission/reception means receives from the outside. An output signal from the scrambler means is recorded on the hard disk. The descrambler means descrambles the signal that is read out of the hard disk. The memory outputs initial values to the scrambler means and the descrambler means. The initial value varying means varies the initial values when the data recorded on the hard disk is erased.
In this data storage device, if data erase of the hard disk is instructed via the transmission/reception means, the initial value varying means generates new initial values for the scrambler means and descrambler means. Data, which is newly recorded, is subjected to a scramble process and a descramble process on the basis of the new initial values.
On the other hand, the data, which has already been recorded on the hard disk before the variation of the initial values, is descrambled on the basis of initial values which are different from the initial values before the variation, and is then reproduced. Accordingly, since the data, which has already been recorded on the hard disk before the variation of the initial values, is descrambled on the basis of initial values which are entirely different from the initial values at the time of data recording, data with different values is read out.
Consequently, since the data, which is stored before the change of the initial values, cannot normally be read out, the change of initial values is virtual erase of the hard disk. Thus, the data can virtually be erased instantaneously, without erase data being overwritten on the hard disk of the data storage device. Thereby, the work time for re-use or discard of the hard disk can remarkably be reduced.
However, according to the conventional data storage device, although decoding of scrambled data is difficult, the take-out of the scrambled data can easily be performed. Thus, it is not possible to deny that the scrambled data may be decoded with the progress of decoding technologies. It is thus required to realize a novel function for surely executing erase of written information and preventing leak of information.